Abstract: The BeiDou-3 Navigation Satellite System (BDS-3) officially commenced global navigation and positioning services in July 2020. Pseudorange single point positioning (SPP) is widely used in vehicle navigation and smart terminal positioning due to its low cost and simple algorithm. Currently, BDS-3 provides open services on the B1I, B3I, B1C, B2a, and B2b frequencies. To systematically evaluate the single-frequency SPP performance of each BDS-3 frequency and investigate the performance of the BDS global ionospheric model (BDGIM), this study develops a single-frequency SPP model applicable to all BDS-3 frequencies. Based on observation data from 22 global stations, the impacts of BDGIM and the GPS Klobuchar model (GPSK8) on positioning accuracy during both active and quiet solar periods are compared and analyzed. Experimental results show that, on a global scale, BDGIM generally outperforms GPSK8, improving positioning accuracy by 15.6% during quiet periods and 11.5% during active periods. Significant improvements are particularly observed in high-latitude and low-latitude regions. Among the single-frequency SPP results for different frequencies, B1C and B1I demonstrate the best positioning performance, with three-dimensional accuracies of 3.31 m and 3.39 m, respectively.